Metallica were called in to pinch-hit for Green Day at this past weekend's Voodoo Music Experience in New Orleans, and during their Saturday night set, they not only delivered the goods but took a little time to pay tribute to Billie Joe and Co.

Two songs into their set — right after "Hit the Lights" and "Master of Puppets" for those keeping score at home — Metallica frontman James Hetfield joked "We! Are! Green Day! ... Except a little taller!" while the NOLA crowed cheered wildly. Later in the set, he also dedicated "Battery" to embattled Green Day frontman Billie Joe Armstrong, saying, "This one's for Billie."

But they didn't stop there. During their encore, Metallica teased fans with the opening chords of Green Day's smash "American Idiot," which was greeted with loud applause. But they cut the cover short, as Hetfield told the crowd, "We can't play that song." He then showed his support for the band, saying, "They're getting it sorted out; hopefully they'll get it fixed because the world needs them."

Green Day were forced to pull out of their headlining slot at Voodoo after Armstrong entered treatment for "substance abuse" in late September. Originally, the band said they'd only miss a few promotional appearances, but soon after Armstrong checked into rehab, producer and Warner Bros. Records chairman Rob Cavallo told Rolling Stone that Green Day might also be forced to scrap parts of their tour, too, saying Armstrong's stint could go on for an "undetermined" length of time.